Characteristics

The Word
Amphibian means “both lives”. Frogs and toads have lives in the water as tadpoles and on land when they are adults.

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Frogs are cold-blooded, meaning they have to rely on the sun to warm up their bodies.
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Most species of frogs are able to hibernate in the winter months.
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Frogs burrow into the soil at sleep off the winter months.

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Two functions: respiration and protection.
Moist to respiration through the skin..
Mucous glands give it a slimy feeling.
Other glands secrete foul tasting or poisonous substances for protection.

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Interlocking vertebrae bear body weight.
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Internal skeleton specialized for jumping.
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Radius and ulna are fused for strength upon impact.
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Tibia and fibula are fused for strength during jumping.

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Much like the human CV system
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2 loops
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Heart to lungs and back to heart
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Heart to body and back to heart

To body
Right atrium
To body
To lungs
Left atrium
Ventricle

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Atriums receive blood from the body and the lungs.
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Ventricle pumps blood to the body and the lungs.
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Valves direct blood with oxygen and blood without oxygen to the right location.
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Mixing of blood with oxygen and blood without oxygen does happen in the frog ventricle.

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Larva- through gills and skin (Tadpole)
Adults- through lungs and skin

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All adults are carnivorous.
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Feed mostly on insects. Larger species may feed on mice, snakes and fish.
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Larva feed on algae or bacteria.

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Mouth
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Elastic esophagus allows for passage of large food.
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Stomach - digestion begins
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Small Intestine
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Large intestine
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Cloaca

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Brain, Spinal Cord, Nerves
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Larva have lateral line (like fish for balance in the water) which most times is lost in metamorphosis to adulthood.
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Eyes are covered by a transparent membrane for protection and vision underwater.
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Hearing is well developed.

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Frogs and humans are vertebrates.
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They have similar organ systems.
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Dissecting a frog helps you learn about human anatomy.

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The eyes and nose of a frog are on top of its head so it can breathe and see most of its body under the water.
A frog can change the color of its skin depending on its surroundings.
Certain frogs can jump up to 20 times their own body length in a single leap.
The world’s biggest frog is the goliath frog from Cameroon in
West Africa. Their body can be one foot long.

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The smallest frogs in the world are less than half an inch long.
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Because frogs come out in the rain, people used to think that they fell to earth in the rain.
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In recent years, a painkiller with 200 times the power of morphine has been found in the skin of a frog.